For example, a known scanning endoscope scans a test site by irradiating light from an optical fiber towards the test site while displacing the emission end of the optical fiber with an optical scanning actuator. This scanning endoscope then detects light that is reflected or scattered at the test site, fluorescent light that is generated at the test site, or other such light (for example, see JP 2010-501246 A (PTL 1)).
In addition to the observation mode for diagnosis, the scanning endoscope disclosed in PTL 1 can operate in many other modes for other purposes, such as a treatment mode. Therefore, as the method for scanning the test site, the method for scanning over the required scanning pattern can be selected from among a plurality of different scanning methods in which the scanning pattern may be a spiral pattern, raster pattern, Lissajous pattern, propeller pattern, or other pattern.